[Revised entry by Anand Vaidya on April 13, 2015.
Changes to: Main text, Bibliography, fig1.png]
Whereas facts about what is actual are facts about how things are, facts about modality (i.e., what is possible, necessary, or impossible) are facts about how things could, must, or could not have been. For example, while there are in fact eleven players on a soccer team, there could have been thirteen, though there couldn't have been zero. The first of these is a fact about what is actual; the second is a fact about what was possible, and the third is a fact about what is impossible. Humans are often disposed to consider, make, and evaluate judgments about what is possible and necessary, such as when we are motivated to make things better and imagine how things might be. We judge that things could have been different than they actually are, while other things could not have been. These modal judgments and modal claims therefore play a central role in human decision-making and in. . .